FILE - In this file photo taken on Thursday, May 30, 2013, Boris Nemtsov, a former Russian deputy prime minister and opposition leader, presents a report claiming widespread corruption during preparations for the 2014 Winter Games in Sochi, at a news conference in Moscow, Russia. Russian police say opposition leader Boris Nemtsov has been shot and killed in Moscow. (AP Photo/Ivan Sekretarev, File)
(The Associated Press)

FILE - In this file photo taken on Saturday, March 15, 2014, Boris Nemtsov, a former Russian deputy prime minister and opposition leader addresses demonstrators during a massive rally to oppose president Vladimir Putin's policies in Ukraine, in Moscow, Russia. Russian police say opposition leader Boris Nemtsov has been shot and killed in Moscow. (AP Photo/Alexander Zemlianichenko, File)
(The Associated Press)

Russian police investigate the the body of Boris Nemtsov, a former Russian deputy prime minister and opposition leader at Red Square with St. Basil Cathidral in the background in Moscow, Russia, Saturday, Feb. 28, 2015. Russia's Interior Ministry says Boris Nemtsov, a leading opposition figure and former deputy prime minister, has been shot and killed near the Kremlin. Nemtsov, a sharp critic of President Vladimir Putin, was killed early Saturday. His death comes just a day before a major opposition rally in Moscow.(AP Photo/Pavel Golovkin)
(The Associated Press)